The present invention relates to combustion systems, and, more particularly, relates to devices for inhibiting formation of oxides of nitrogen by combustion systems.
As a result of the combustion process, combustion systems normally generate gaseous combustion products which include oxides of nitrogen (NO.sub.x) which are vented to atmosphere as flue gas. It is desirable to limit these NO.sub.x emissions since NO.sub.x is considered a pollutant and combustion systems sold in certain jurisdictions must meet strict NO.sub.x emission standards.
One technique for limiting NO.sub.x emissions from a combustion system is to control peak combustion flame temperatures and residence times at these peak combustion flame temperatures to minimize the formation of NO.sub.x. For example, a supplemental air flow may be provided for cooling a combustion flame in a combustion system, or the combustion process of a combustion system may be otherwise altered to minimize the formation of NO.sub.x. However, these techniques, while limiting NO.sub.x formation, may adverely affect the combustion process of the combustion system by causing incomplete combustion and/or by adversely affecting the combustion process in other ways. Also, these techniques may require a major redesign of certain components of the combustion system, such as a redesign of burners for the combustion system, thereby rendering these techniques undesirable for retrofitting existing combustion systems.